Apparatus and method for determining projectile impact locations

ABSTRACT

This invention relates to an apparatus and method for determining projectile impact locations and, in a specific application, to determining a golfer&#39;s performance in using a particular club, such as a specific iorn. The apparatus has an array of a plurality of vibration sensors distributed in a predetermined pattern in a target area, each of which generates a signal indicative of the sensing of vibration, a processor connected for receiving sensor signals generated and for processing received sensor signals for determining a location of projectile impact relative to the locations of sensors in the target area and for generating an electrical location signal, and a display connected with the processor for receiving the location signal and for displaying to an observer a representation of the location of projectile impact in the target area.

FIELD AND BACKGROUND OF INVENTION

This invention relates to an apparatus and method for determiningprojectile impact locations and, in a specific applications, todetermining a golfer's performance in using a particular club, such as aspecific iron.

The location of impact of a projectile is of interest in a number ofdifferent fields, from military to sports, and may include such subjectsas range determination for firearms and for sports projectiles such asgolf balls and the like. Various apparatus and methods have beenproposed heretofore to determining locations of impact and for providinginformation about such locations to an interested user, from anartillery range officer to a ball player or golfer. Examples may befound in such prior patents as Pence U.S. Pat. No. 2,054,604; Smith U.S.Pat. No. 2,743,929; and Cornell U.S. Pat. No. 3,643,959.

None of these prior patents provide information in a manner which isparticularly helpful to the skilled person attempting to improveexisting skills by having better knowledge of exactly what performancecan reasonably be anticipated. Particularly with a golfer, knowledge ofthe statistically best choice of club for achieving a particular yardagemay open the possibility of a significant improvement in the golfer'sgame. However, such information has essentially been unavailable togolfers prior to the present invention, inasmuch as range information(that is, the distance of impact location from the tee or point ofstriking the ball) is extremely difficult to derive with any accuracyfrom driving range practice.

BRIEF DESCRIPTION OF INVENTION

With the foregoing in mind, it is an object of this invention to providean interested person with accurate information about the location orimpact of a projectile. In realizing this object, vibration sensors aredistributed through a target area and signals are gathered from thesensors and processed to determine the location of impact. Dataregarding the location of impact of a plurality of projectiles aregathered and analyzed statistically to generate an output to a userwhich is useful in learning the range and distribution of the impacts.

Another object of this invention is to equip a golf driving range withan instrument which is capable of assisting a golfer seeking to improvegolf skills by providing greater knowledge about range achieved with aparticular club and the statistical distribution of shots around atarget range. In realizing this object of the present invention,vibration sensors arranged in a geometric array on the surface of orembedded in a golf driving range are polled on a continuing basis by adata processing computer, and sensed vibrations are distinguished tolocate the point of impact of a golf ball. Data regarding the locationsof impact are then accumulated over time and analyzed to provide astatistical analysis of an individual golfer's performance.

Yet another object of this invention is to provide a training exercisefor a golfer in accordance with a method in which locations of impact ofgolf balls are sensed by the sound of impact, the location is determinedby a triangulation process, and the data developed from a series ofimpacts are analyzed statistically to generate a report valuable to askilled golfer seeking to improve golfing skills.

BRIEF DESCRIPTION OF DRAWINGS

Some of the objects of the invention having been stated, other objectswill appear as the description proceeds, when taken in connection withthe accompanying drawings, in which:

FIG. 1 is a somewhat schematic view of a golf driving rangeincorporating the present invention;

FIG. 2 is a block diagram representation of the apparatus of thisinvention;

FIG. 3 is a diagram illustrating the manner in which a position ofimpact is determined from vibration data derived from a plurality ofsensors'

FIG. 4 is a schematic plan view of a target area such as that of thedriving range of FIG. 1, illustrating the installation of a plurality ofsensors in a geometric array; and

FIG. 5 is a representation of a form of statistical report generated inaccordance with the method of this invention.

DETAILED DESCRIPTION OF INVENTION

While the present invention will be described more fully hereinafterwith reference to the accompanying drawings, in which a preferredembodiment of the present invention is shown, it is to be understood atthe outset of the description which follows that persons of skill in theappropriate arts may modify the invention here described while stillachieving the favorable results of this invention. Accordingly, thedescription which follows is to be understood as being a broad, teachingdisclosure directed to persons of skill in the appropriate arts, and notas limiting upon the present invention.

Referring now more particularly to the accompanying Figures, the presentinvention will be described with particular reference to its applicationas a golf training and teaching tool. However, the person skilled inother projectile ranging applications, such as military or other sportsapplications, will be readily able to envision applications of theinvention to be described in such other fields, and thus the followingdescription is to be understood as contemplating such broaderapplications.

The apparatus of the present invention is used in conjunction with asuitable driving range or the like, such as that shown in FIG. 1. Suchranges typically have a tee area 10 from which golf balls are struck anda relatively open target area 11 into which balls are hit. In accordancewith this invention, an array of a plurality of vibration sensors 12 aredistributed in a predetermined pattern in the target area 11, each ofthe sensors for generating an electrical sensor signal indicative of thesensing of vibration. In a preferred form for the invention and where apermanent installation is to be made, the sensors 12 respond to audiblevibrations or sound, and may thus be in the form of microphones,embedded or buried in the ground of the target area 11. Where aninstallation is to be portable, surface mounted microphones may be used.

In accordance with important features of this invention, an electricalprocessor (14 in FIG. 2) is electrically connected with the sensors 11for receiving sensor signals generated thereby; processing receivedsensor signals for determining a location of projectile impact relativeto the locations of the sensors in the target area; and generating anelectrical location signal. The processor preferably takes the form of amicrocomputer using, for example only, an 80386 CPU chip and capable ofoperating at a clock speed on the order or 16 megahertz or more, forreasons which will become more clear hereafter. Before reaching theprocessor, the sensor signals may be filtered, preamplified, and passedthrough certain detection and threshold circuits as will be describedhereinafter.

The processor operates to determine the location of ball impact by aprocess of triangulation using signals from a plurality of sensors. Moreparticularly, and referring to FIG. 3, comparing the time of arrival ofthe sound of an impact at a pair of sensors (such as sensors located atpoints A and B in the Figure) permits determination of a hyperbola onwhich the ball landed, such as the two hyperbolic arms which extendsomewhat vertically in FIG. 3. Where three sensors are used, twohyperbola result from the determination, and the ball is located ashaving landed at the intersection of the hyperbolic arms. While two suchintersections are possible (see FIG. 3), the relative times of sensingwill enable a discrimination of which intersection is in fact closer tothe common sensor, thereby definitely locating the ball impact at thepoint I.

It has been determined that golf ball impact sounds have certaincharacteristics which are employed to advantage in the presentinvention. More particularly, the sound of impact varies somewhat withground conditions. However, such sounds have been reliably detected whenimpact occurred within twenty five yards of a microphone. Over a rangeof ground conditions, the frequency of the sound of impact falls withina band width of from about 600 hz to about 1400 hz.

In accordance with the present invention, sensors are distributed over ahorizontal target area (such as a golf driving range) in a predeterminedgeometrical array. The use of an array is chosen to enable coverage of atarget area consistent with that in which balls will be landing, thatis, generally an elongate, rectangular area. In order to provide apattern of sensors which is easily rationizable for data processing,provides reliable detection of impact, and is easily expanded orcontracted to fit varying area, the geometric array is preferably chosento include a number of triangles, arranged in hexagons. Such a hexagonarray (shown in plan view in FIG. 4) has the caapability of sensing balllandings over an extended range and being easily expandable widthwise tocover enlarged areas if desired.

In arranging the apparatus of this invention, it is preferred that eachsensor or microphone 11 have an associated filter and preamplifier tolimit the signals forwarded to the desired bandwidth and provide someboost in signal levels. Such sensor units may be joined through junctionboxes 15 (FIG. 2) to one or more receivers 16 which provide furtheramplification and then to logic circuits 18 which perform certainpreliminary logic steps. For example, it is desirable to screen out thesignals to be processed by the microprocessor 14 randomly or slowlyfluctuating background noise, which for present purposes is any signalwhich has a rise time significantly less than that of a ball impactsound, such as a passing automobile, wind, etc. In an operatingembodiment of the invention, such screening was accomplished by use of acomparator having a settable threshold which must be exceeded for signalpassage and which makes an ongoing comparison of signals to separatedetection of a sharply rising signal from detection of a more slowlyrising signal and discard the latter. The logic circuits may alsoinclude timing circuits which respond to the first sensor signal ofimpact by opening a window of time in which second and third sensorsignals of impact will be sought in order that the discrimination ofimpact location may be performed.

The processor 14 has associated memory for storing a plurality oflocation signals and functions for compiling and comparing sets oflocation signals indicative of the impacts of a succession ofprojectiles. In particular, the processor 14 performs a statisticalanalysis of a set of location signals for developing a teaching aid fora golfer which will clarify for the golfer the performance actuallyaccomplished with specific clubs. The processor 14 performs an analysisof a set of location signals for determining the distribution of thesignals in the set about a predetermined location, and preferably indistance from a predetermined location along a predetermined axis, suchas in yards from the tee 10.

The statistical data generated and stored by the processor 14 issupplied, in the form of an electrical signal, to a display which iselectrically connected with the processor for receiving a locationsignal and for displaying to an observer a representation of thelocation of projectile impact in the target area. One example of such arepresentation is illustrated in FIG. 5, in a form which may eitherappear as a visual display on a visual display device such as a CRT orLCD display or be printed out by a suitably driven printer device. Thedisplay may include identifying data for the user, the date and otherconditions such a club used and then present data regarding the normalrange for the club used and the distribution of impacts or landings fromor about that range. A particularly useful display is a curve of bestfit, shown in the lower portion of FIG. 5, for the data, which willgraphically illustrate for a golfer the "high percentage" shot for theclub undergoing evaluation.

As will be appreciated by the thoughtful reader, the practice of themethod of this invention will include the steps of generating aplurality of electrical signals indicative of the sensing of vibrationaffecting an array of a plurality of vibration sensors distributed in apredetermined pattern in a target area; receiving the sensor signals atan electrical processor and processing received sensor signals fordetermining a location of projectile impact relative to the locations ofthe sensors in the target area and for generating an electrical locationsignal; and displaying to an observer a representation of the locationof projectile impact in the target area. The signals generated may begenerated in response to air borne or ground transmitted vibration,which may be in an audible range of frequencies. The method will includethe step of distributing sensors through the target area in a patternwhich is a geometric array and the step of storing a plurality oflocation signals in a set and compiling and comparing sets of locationsignals indicative of the impacts of a succession of projectiles. Astatistical analysis of a set of location signals is performed toprovide insight for the user in the performance monitored by theprocess, preferably by determining the distribution of the signals inthe set about a predetermined location.

In the drawings and specifications there has been set forth a preferredembodiment of the invention and, although specific terms are used, thedescription thus given uses terminology in a generic and descriptivesense only and not for purposes of limitation.

What is claimed is:
 1. An apparatus for assisting in the evaluation oftargeting of an impacting golf ball and comprising:an array of aplurality of vibration sensor means distributed in a predeterminedregular geometric pattern which defines a target area which is agenerally elongate, generally rectangular, generally horizontal surfacearea located remotely from a point from which a golf ball is dispatchedtoward the target area, each said sensor means for generating anelectrical sensor signal indicative of the sensing of vibration,electrical processor means electrically connected with said sensor meansfor receiving sensor signals generated thereby and for processingreceived sensor signals for determining a location of golf ball impactat any point within said target area spaced lengthwise or widthwisethereof relative to the locations of said sensor means in the targetarea and for generating an electrical location signal, memory meanselectrically connected with said processor means for receiving andstoring a plurality of location signals, said processor means and saidmemory means cooperating for compiling and comparing sets of locationsignals indicative of the impacts of a succession of golf balls, anddisplay means electrically connected with said processor means forreceiving said location signal and for displaying to an observer arepresentation of the locations of golf ball impact in the target area.2. An apparatus according to claim 1 further comprising comparator meanselectrically connected with said sensor means and said processor meansfor receiving sensor signals generated by said sensors means and formaking an ongoing comparison of signals to separate detection of asharply rising signal from detection of a more slowly rising signal anddiscard the latter.
 3. An apparatus according to claim 1 furthercomprising timing means electrically connected with said sensor meansand said processor means for responding to a first sensor signal ofimpact by opening a window of time in which second and third sensorsignals of impact will be sought in order that a discrimination ofimpact location may be performed.
 4. Apparatus according to claim 1wherein said pattern is composed of triangles.
 5. Apparatus according toclaim 1 wherein said patterns is composed of hexagons.
 6. Apparatusaccording to claim 1 wherein said processor means performs an analysisof a set of location signals for determining the distribution of thesignals in the set in distance from a predetermined location along apredetermined axis substantially corresponding to the direction offlight of the golf balls.
 7. Apparatus according to claim 6 wherein saidprocessor means generates a display signal representative of a curve ofbest fit to the distribution of the signals in the set in distance fromthe predetermined location along the predetermined axis.
 8. An apparatusfor assisting in the evaluation of targeting of an impacting golf balland comprising:an array of a plurality of vibration sensor meansdistributed in a predetermined regular geometric pattern which defines atarget area which is a generally elongate, generally rectangular,generally horizontal surface area located remotely from a point fromwhich a golf ball is dispatched toward the target area, each said sensormeans for generating an electrical sensor signal indicative of thesensing of vibration, electrical processor means electrically connectedwith said sensor means for receiving sensor signals generated therebyand for processing received sensor signals for determining a location ofgolf ball impact at any point within said target area spaced lengthwiseor widthwise thereof relative to the locations of said sensor means inthe target area and for generating an electrical location signal,comparator means electrically connected with said sensor means and saidprocessor means for receiving sensor signals generated by said sensorsmeans and for making an ongoing comparison of signals to separatedetection of a sharply rising signal from detection of a more slowlyrising signal and discard the latter, timing means electricallyconnected with said sensor means and said processor means for respondingto a first sensor signal of impact by opening a window of time in whichsecond and third sensor signal of impact will be sought in order that adiscrimination of impact location may be performed memory meanselectrically connected with said processor means for receiving andstoring a plurality of location signals, said processor means,comparator means, timing means and memory means cooperating forcompiling and comparing sets of location signals indicative of theimpacts of a succession of golf balls, and display means electricallyconnected with said processor means for receiving said location signaland for displaying to an observer a representation of the locations ofgolf ball impact in the target area.